1. Field of the Invention
The present invention relates to a latch device to be equipped in a door of an in-flight meal server (service cart) of an airplane and the like.
2. Description of the Prior Art
FIG. 1 is a schematic view showing the outline of the in-flight meal server.
The in-flight meal server shown as a whole by the reference number 1 has a box-shaped body 10, and the body 10 is supported by a caster 12. A door 20 is fixed to the front and back of the body 10 by a hinge 22 so that it may be opened and closed.
The door 20 may be locked to and unlocked from the body 10 by a latch device 30.
FIG. 6 is an explanatory view of the door 20 equipped with a conventional latch device.
A latch device 30 has a handle 31. The handle 31 is fixed so that it may be rotated to the direction moving away from the door through an axis portion 32 on its upper portion. The handle 31 is connected to a lever 36, and the lever 36 is supported rotatably by a pin 34.
When the handle 31 is pulled toward a user, the lever 36 connected to the handle 31 rotates to the arrow A direction with the pin 34 at the center of rotation.
A lever 36 is connected to three bolts 41, 42 and 43 through link rods 45, 46 and 47.
The three bolts 41, 42 and 43 each fit into a catch formed on the body 10 side when protruded, thereby locking the door. When the lever 36 is rotated to the arrow A direction, each link rod pulls in the respective bolt to the door so that the bolt is separated from the catch, and the door is unlocked.
The in-flight meal server is kept at an appropriate position in the galley of the airplane before and after the meal service. At this position, the door is maintained at a locked state by independent primary and secondary devices. Each one of the independent devices is required to satisfy the strength requirement under a predetermined load.
However, in the prior latch device shown in FIG. 6, the lever 36 and each bolts 41, 42 and 43 were directly connected to each other through the link rod, so they were regarded as an independent primary device. Accordingly, a turn retainer positioned in the galley of the airplane was the only secondary device, so there were cases where it was difficult for each of the devices alone to satisfy the strength requirement under the predetermined load.
The present invention provides a latch device solving the problems mentioned above.
The door latch device of the present invention is equipped with a main latch device as the primary device positioned near the handle for operating the latch, and an auxiliary latch device as the secondary device which is connected to the main latch device through a link mechanism. The auxiliary latch device is equipped with an operating portion formed on the surface of the door, a cylinder-shaped body fixed to the interior of the door, a slider inserted slidably to the body, a bolt formed integrally with the slider, a spring biasing the slider to the unlocking direction, and a knob for manually operating the slider so as to secure its independence.
Therefore, by the combination of the turn retainer positioned in the galley of an airplane and the auxiliary latch device as the secondary device, each of the independent devices alone satisfies the strength requirement under the predetermined load.
Further, the operating portion is equipped with a guide groove for guiding the knob, and a lock groove for maintaining the knob in a locked position, as well as a colored plate formed on both sides of the knob for indicating the locked or unlocked state through the guide groove to the exterior.